Pickproof lock

ABSTRACT

A key-operated lock mechanism has a tumbler support carrying spring-loaded tumblers which may be moved in their keyway passages by the fingers of a key insertable through a keyhole so that depending pins on a pivotal detent are aligned therewith in an unlocked position. When in the locked position, the pins merely contact the upper surfaces of the tumblers. A guard depends from the detent between the keyhole and the keyway so that the key fingers lift the guard and upwardly pivot the detent upon movement of the key towards the keyway. The key has an aperture receiving the guard when the fingers align the tumbler holes with the detent pins to permit the detent to pivot downwardly into the unlocked position.

United States Patent Primary ExaminerRobert L. Wolfe Attorney- Kurt Kelman ABSTRACT: A key-operated lock mechanism has a tumbler support carrying spring-loaded tumblers which may be moved in their keyway passages by the fingers of a key insertable through a keyhole so that depending pins on a pivotal detent are aligned therewith in an unlocked position. When in the locked position, the pins merely contact the upper surfaces of the tumblers. A guard depends from the detent between the keyhole and the keyway so that the key fingers lift the guard and upwardly pivot the detent upon movement of the key towards the keyway. The key has an aperture receiving the guard when the fingers align the tumbler holes with the detent pins to permit the detent to pivot downwardly into the unlocked position.

PATENTEU SEPI 4 |97| SHEET 1 [1F 2 ATTORNEYS w J ,0 I 0 a 4 w a; m W m i I Z w- J W 3 2 an] Z My n Imam! A PICKPROOF LOCK The present invention relates to an improvement in locks, more specifically to a pickproof lock operated according to a completely novel principle.

Tumbler locks are and have been well known in the art for any years. These devices are usually generally cylindrical in nature andhave a plurality of bores in alignment with their axes perpendicular to the axis of the lock. Mounted in these bores are a series of split cylinders which constitute the tumblers. The lengths of these cylinders vary and the lock cannot be turned unless all of the splits of the tumblers are precisely aligned at the interface between the stationary housing and the'rotating portion of the lock. A metal key is provided which is ground in such a manner as to line up these tumblers properly.

Such locks suffer from many disadvantages the principal one being that they can be readily picked by an expert locksmith. Moreover, a person with sensitive fingers and hands can feel the proper position of the tumblers and can open the lock by virtue of his skill.

Moreover, as is well known, a locksmith can manufacture a key without great difficulty by inserting a probe into the lock and feeling each tumbler. This, of course, leaves locks of this character open to picking, particularly when they are located in a secluded area.

It is therefore among the objects of this invention to provide a lock which is suitable for use on an ordinary household door or automobile ignition which is pickproof.

It is also among the objects of this invention to provide such a lock which is capable of a very large number of separate combinations.

It is further among the objects of this invention to provide "such alock which will be useful with existing subsidiary lock mechanisms.

In practicing the present invention, there is provided a housing adapted to be'fixed in place and having a hollow generally cylindrical interior. Such a housing is of the same size and external shape'as standard lock housings. However, the housing used for the present lock has a longitudinal slot at least part way down the 'wall thereof and extending through the wall. A tray, is provided in the interior and is rotatable relative thereto. The tray contains several axialpassages defining a keyway, each of which contains a spring-loaded tumbler.

There is a keyhole in one end of the housing communicating and aligned with the keyway. Each tumbler has a hole in its upper surface and is slidably mounted in a respective passage.

A detent'is pivotally mounted at a point adjacent the end of the tray remote from the keyhole. The detent pivots between an unlocked position and-a locked position and has depending pins respectively adapted to contact the upper surface of the tumblers through bores in the tray.

When the detent is in the locked position the hole in the tumbler is out of alignment with the associated pin and the pin rests on the upper surface of the tumbler. At the same time the detent projects radially outwardly into the slot in the housing thereby preventing rotation of the tray relative to the housing.

When the detent is in the unlocked position there is provided an aligning, means for lining up the hole with the pin. This aligning means takes the form of a key having a finger adapted to enter the passage, the length of the finger being such that when the key is entirely in the lock the hole is aligned with the pin.

As a'result, the pin is at least partly in the hole and the detent h'aspivoted radially inwardly so as to be clear of the slot. The lock is thereby opened.

By'varying'the position of the hole in each of the tumblers the multiple combinations of, lock are obtained.

It is recognized, of course, that the lock as hitherto described, while novel, couldbe picked. lt is only necessary to have a plurality'of long thin pieces of metal, each of which will enter one of the passages. The skilled locksmith can press on the face of each tumbler and feel the point at which the pin begins to enter the hole. ln order to prevent such picking there is provided a depending guard on the detent such that, when w release position is achieved by permitting the defe ntto pivot still further radially outwardly than the locked position so that the guard is out of alignment with the keyhole and the keyway There is provided an entry cam on the front surface of the guard in order to facilitate its movement to the release position.

At the same time the aligning means or key is provided with an aperture which is on the portion of the key away from the fingers. This aperture is of such size and shape that the guard can pass through it. When the key is fully in the lock, the guard passes through the aperture so that the detent may pivot to its unlocked position. I

It will be appreciated that with the guard as heretofore described, it is not possible to pick the lock. Should a piece of metal be inserted the guard will be moved thereby out ofalignment with the keyhole, thereby radially outwardly pivoting the detent to its release position so that the depending pin or pins will be out of contact with the upper surfaces of the tumblers. Therefore it will not be possible for even a highly skilled locksmith to determine at what position the tumblers will permit the entry of the pin so that the detent will assume its unlocked position. I

To assist in inserting the key, an alignment entry cam is provided on at least one of the fingers at the end which enters the passage. Such a cam can be simply a beveled end substantially complementary to the entry cam.

For purposes of withdrawal, there is provided a withdrawal cam on the guard on the surface thereof nearer the passage together with a complementary cam on the edge of the aperture nearer the finger.

Under normal circumstances, it will be sufficient to permit the force of gravity to bring the detent from its release or locked position to the unlocked position. Normally, the pins if properly arranged in the lock will simply fall into the aligned holes and permit the detent to assume the unlocked position. However, it may be that a more positive action is desired either because the lock cannot be mounted so that the force of gravity is effective, or simply because one does not wish to rely on a passive type of movement.

To accommodate this situation, there is provided a return means urging the detent towards its unlocked position upon the entry of the aligning means. The return means consists of a base on the end of the detent remote from the keyhole. The

bearing surface of the base nearer the keyhole constitutes the stop means against which the spring means rests. There are flanges on the end of the tray remote from the keyhole having pivot holes therein. There is also a bore in the base generally perpendicular to the detent and in register with the pivot holes. An axle is fitted in the bore and pivot holes and the detent pivots thereabout. The bearing surface in contact with'the spring means is located below the axle or pivot point. Thus when the key is inserted and the spring means compressed the reaction will bear against the bearing surface. Since this surface is below the pivot point it will by virtue of the moment arm between the point of contact of the spring means and the bearing surface and the axle, urge the detent towards its unlocked position. In this form of the device the desired movement can be obtained regardless of thepositioning of the'detent. In fact, such a mechanism will operate quite satisfactorily even if upside down.

it is of course recognized that the rotary motion of the lock mechanism as described herein will be converted to the sliding motion to actuate the bar or latch on a door or similar device.

locks produce the same rotary motion, the existing mechanism for converting it to sliding motion is useable with the present device.

In the accompanying drawings, in which like reference numerals refer to like parts, and in which:

FIG. 1 is an exploded perspective view of the locking mechanism of the present invention with some parts broken away for clarity;

FIG. 2 is a longitudinal cross section of the assembled mechanism in the locked position;

FIG. 3 is a cross-sectional view along line 3-3 of FIG. 2;

FIG. 4 is a cross-sectional view along line 44 of FIG. 2;

FIG. 5 is a cross-sectional view along line 5-5 of FIG. 3, showing the mechanism in locked position prior to insertion of the alignment means;

FIG. 6 is a view similar to that of FIG. 5 after the insertion of the locking means; and

FIG. 7 is a view similar to that of FIG. 2 with the mechanism in the unlocked position.

The locking mechanism 1 of the present invention comprises a housing 2, a barrel 3 and a tray 4. A detent 5 is also provided.

Housing 2 is provided with slot 7 generally longitudinal of its wall and extending therethrough. Housing 2 is also provided with means for fastening the housing to the door or other device to be locked in the form of ears 8. The interior of I housing 2 is preferably generally cylindrical in shape and adapted to receive barrel 3 and tray 4.

Barrel 3 has keyhole 10 in an end wall thereof and longitudinally extending slot 9. Barrel 3 is rotatable relative to housing 2 and carries tray 4 in the interior thereof and for rotation therewith. Slot 7 and channel 9 are in register with one another at at least one position of rotation of barrel 3. The slot and the channel are of such shape as to permit detent 5 to pass therein and therethrough.

Tray 4 can be of any convenient shape but is shown in the drawings as being substantially rectangular. It is provided with a keyway consisting of plurality of passages 14 each extending therethrough. Tumblers 6 rest in each of passages 14 of the tumbler support 3, 4, and carry holes 11 on the upper surface thereof. Springs 12 are located in passages 14 between tumblers 6 and bearing surface 32 of a detent abutment. Tumblers 6 are preferably provided with faces 13 against which the key 29 bears when the lock is being opened.

1 Tray 4 in its preferred embodiment is provided with a plurality of flanges 16 extending in a direction away from keyhole 10. For most convenient construction, flanges 16 are simply extensions of the walls between passages 14 and the walls between the outermost passages 14 and the side tray 4. Pivot holes 17 are provided in flanges 16 in registry with pivot hole 25 in abutment 21 of detent 5, pivot pin 18 extending through the registering pivot holes. The top of tray 4 carries bores each of which communicates with one of passages 14.

Detent 5 consists of a substantially longitudinally extending rod having a crossbar 20 intermediate its ends. Depending from crossbar 20 are pins 23 which are in alignment with bores 15 and are adapted to pass therethrough.

Detent 5 has a depending guard 19 at the end thereof nearer keyhole l0 and normally in alignment therewith. Guard 19 is provided with beveled cam and oblique faces 31.

At the other end of detent 5 is base 21 with slits 22 adapted to receive flanges 17. When the detent is mounted on tray 4 by passing pivot pin 18 through holes in the barrel and registering pivot holes 17 and 25, detent 5 can freely pivot on the barrel about the pin.

To describe the operation of lock 1, it will be assumed that, at the outset, it is in the locked position shown in FIG. 2. Key 29 having fingers is inserted into keyhole 10. At the end of fingers 35 are alignment face cams 36 adapted to bear against entry cam 30 on guard 19. The pressure of key 29 causes guard 19, and hence detent 5 to move out of alignment with the keyhole as shown in the direction of the arrow in FIG. 2, into the release position. This movement permits key 29 to enter the lock and fingers 35 each to enter one of passages 14 and depress tumblers 6 against the bias of springs 12. The length of fingers 35 is such that each finger will bring the hole 11 on the tumbler 6 which it contacts into alignment with associated bore 15 and permit associated pin 23 to pass through the respective base.

At the same time, the entry of key 29 in moving tumblers 6' away from keyhole 10 compresses springs 12. Thereaction to this compression occurs at bearing surface 32 which is below bore 25 and pivot pin 18 thereby urging detent 5 radially in-"= wardly to its unlocked position the key having an aperture 33- i for receiving guard 19 when the key has been moved inwardly. This action is shown in FIGS. 5-7.

As can be seen in FIG. 7, detent 5 has pivoted radially inwardly about pivot pin 18 into the unlocked position. Aperture 33 in key 29 has permitted guard 19 to pass therethrough. Pins 23 have passed through bores 15 and entered holes 11. Detent 5 is clear of slot 7 in housing 2 and the lock is thus free to turn.

When the key is removed, alignment withdrawal cam 34 on key 29 bears against cam face 31 on guard 19, thereby moving detent 5 in the direction shown by the arcuate arrow in FIG. 7. During this movement, detent 5 first moves radially outwardly to the release position in which guard 19 is clear of keyhole 10. When the key is removed, detent 5 under the urging of still compressed springs 12 returns to the locked position as shown in FIG. 2. I

As can be seen from the foregoing description and the annexed drawings, the lock as shown and described thus far is such that the key cannot be removed while the lock is in opened position. This is because a turn of the lock barrel brings detent 5 to a position where it is no longer in register with slot 7 and hence it cannot move radially outwardly its release position since guard 19 is engaged in key aperture 33. Key 29 is therefore locked in the hole 10. This type of lock is desirable for certain applications, particularly for use in automobiles. In such situations it is desired that it be made impossible for the operator to remove the key from the ignition while the engine is still running.

Further, there are also applications wherein it may be deemed desirable to permit removal of the key while the door is unlocked. The present device can be readily adapted to do this by either of two simple expedients. If the sliding mechanism of the lock is made such that it requires a 360 rotation of the locking mechanism to open it, then in the unlocked position of the bolt detent 5 will be in the position shown in FIG. 7 and the key can be removed. Alternatively, an additional slot can be cut in housing 2 at a point 180 removed from slot 7. Thus when the bolt is withdrawn there is another slot through which detent 5 can project and assume its release position in order to permit withdrawal of key 29.

FIG. 1 also shows a means for securing the parts of the lock together. This constitutes panel 26 having cross opening 27 secured to barrel 3 by screws 28. This portion of the device is substantially standard on existing locks and forms no part of the present invention.

What is claimed is:

l. A key-operable lock mechanism comprising 1. a tumbler support, the tumbler support having a. a keyhole in one end thereof,

b. a keyway in the interior thereof and aligned with the keyhole, the keyway defining a plurality of passages,

c. a spring-loaded tumbler slidably mounted in each of said passages, each tumbler being biased towards the keyhole and having a hole in the upper surface thereof, and

d. a guide slot extending in the direction of the keyway and above the upper surface of the tumblers.

2. a detent having one end remote from the keyhole freely pivotally mounted on the tumbler support for pivotal movement in the guide slot between a locked and an unlocked position, the detent including a. a plurality of pins depending therefrom and each pin in contact with the upper surface of a respective one of the tumblers in the locked position of the detent, and

b. a guard depending from the other end of the detent between the keyhole and the keyway; and

3. a key for insertion through the keyhole and into the keyway, the key having a. a plurality of fingers adapted to lift the guard upon movement of the key towards the keyway whereby the detent is upwardly pivoted and the detent pins are moved out of contact with the upper surfaces of the tumblers, and subsequently to move into corresponding ones of the keyway passages for aligning the holes of respective ones of the tumblers with respective ones of the pins depending from the detent, and

. an aperture in the key for receiving the guard when the fingers align the tumbler holes with the detent pins whereby the pins enter into the tumbler holes and the guard enters into the key aperture to permit the detent to pivot downwardly into the unlocked position.

2. The key-operable lock mechanism of claim 1, wherein the detent has a depending abutment at the one end thereof, compression springs for biasing the tumblers towards the keyhole being mounted in the keyway passages between the tumblers and the detent abutment.

3. The key-operable lock mechanism of claim 1, further comprising a housing having a generally cylindrical interior, the tumbler support being correspondingly cylindrical and received in the housing interior for rotation in respect thereto, and a longitudinally extending slot in the housing, the guide slot in the tumbler support being in alignment with the housing slot in the locked position and the detent extending into the housing slot in said position to prevent rotation of the tumbler support in the housing, and the detent being pivoted out of engagement with the housing slot in the unlocked position to enable the tumbler support to be rotated.

4. The key-operable lock mechanism of claim 1, wherein the tumbler support has a plurality of bores in alignment with the detent pins and above the upper surfaces of the tumblers for guiding the pins.

5. The key-operable lock mechanism of 4, wherein the tumbler support comprises a barrel and a tray in the interior of the barrel, the tray defining the keyway passages and having atop wall covering said passages and defining the bores in alignment with the detent pins.

6. The key-operable lock mechanism of claim 1, wherein the guard has beveled end faces for ready sliding contact with the key fingers and aperture upon movement of the key into and out of the keyway.

7. The key-operable lock mechanism of claim 1, further comprising a return means urging the detent to pivot into the unlocked position upon alignment of the tumbler holes with the detent pins.

8. The key-operable lock mechanism of claim 7, further comprising a pivot pin, the detent has a depending abutment at the one end thereof, the tumbler support has flanges at the end thereof remote from the keyhole and the keyway passages extending between said flanges, the detent abutment being slotted to receive the tumbler support flanges, the abutment and the flanges having aligned bores receiving the pivot pin whereby the detent is pivotal about the pivot pin on the tumbler support, and said return means being compression springs mounted in the keyway passages between the tumblers and the detent abutment.

9. The key-operable lock mechanism of claim 1, wherein at least one of the detent pins is longer than the other pins whereby the other pins do not contact the upper surfaces of respective ones of the tumblers in the locked position. 

1. A key-operable lock mechanism comprising
 1. a tumbler support, the tumbler support having a. a keyhole in one end thereof, b. a keyway in the interior thereof and aligned with the keyhole, the keyway defining a plurality of passages, c. a spring-loaded tumbler slidably mounted in each of said passages, each tumbler being biased towards the keyhole and having a hole in the upper surface thereof, and d. a guide slot extending in the direction of the keyway and above the upper surface of the tumblers.
 2. a detent having one end remote from the keyhole freely pivotally mounted on the tumbler support for pivotal movement in the guide slot between a locked and an unlocked position, the detent including a. a plurality of pins depending therefrom and each pin in contact with the upper surface of a respective one of the tumblers in the locked position of the detent, and b. a guard depending from the other end of the detent between the keyhole and the keyway; and
 3. a key for insertion through the keyhole and into the keyway, the key having a. a plurality of fingers adapted to lift the guard upon movement of the key towards the keyway whereby the detent is upwardly pivoted and the detent pins are moved out of contact with the upper surfaces of the tumblers, and subsequently to move into corresponding ones of the keyway passages for aligning the holes of respective ones of the tumblers with respective ones of the pins depending from the detent, and b. an aperture in the key for receiving the guard when the fingers align the tumbler holes with the detent pins whereby the pins enter into the tumbler holes and the guard enters into the key aperture to permit the detent to pivot downwardly into the unlocked position.
 2. a detent having one end remote from the keyhole freely pivotally mounted on the tumbler support for pivotal movement in the guide slot between a locked and an unlocked position, the detent including a. a plurality of pins depending therefrom and each pin in contact with the upper surface of a respective one of the tumblers in the locked position of the detent, and b. a guard depending from the other end of the detent between the keyhole and the keyway; and
 2. The key-operable lock mechanism of claim 1, wherein the detent has a depending abutment at the one end thereof, compression springs for biasing the tumblers towards the keyhole being mounted in the keyway passages between the tumblers and the detent abutment.
 3. a key for insertion through the keyhole and into the keyway, the key having a. a plurality of fingers adapted to lift the guard upon movement of the key towards the keyway whereby the detent is upwardly pivoted and the detent pins are moved out of contact with the upper surfaces of the tumblers, and subsequently to move into corresponding ones of the keyway passages for aligning the holes of respective ones of the tumblers with respective ones of the pins depending from the detent, and b. an aperture in the key for receiving the guard when the fingers align the tumbler holes with the detent pins whereby the pins enter into the tumbler holes and the guard enters into the key aperture to permit the detent to pivot downwardly into the unlocked position.
 3. The key-operable lock mechanism of claim 1, further comprising a housing having a generally cylindrical interior, the tumbler support being correspondingly cylindrical and received in the housing interior for rotation in respect thereto, and a longitudinally extending slot in the housing, the guide slot in the tumbler support being in alignment with the housing slot in the locked position and the detent extending into the housing slot in said position to prevent rotation of the tumbler support in the housing, and the detent being pivoted out of engagement with the housing slot in the unlocked position to enable the tumbler support to be rotated.
 4. The key-operable lock mechanism of claim 1, wherein the tumbler support has a plurality of bores in alignment with the detent pins and above the upper surfaces of the tumblers for guiding the pins.
 5. The key-operable lock mechanism of 4, wherein the tumbler support comprises a barrel and a tray in the interior of the barrel, the tray defining the keyway passages and having a top wall covering said passageS and defining the bores in alignment with the detent pins.
 6. The key-operable lock mechanism of claim 1, wherein the guard has beveled end faces for ready sliding contact with the key fingers and aperture upon movement of the key into and out of the keyway.
 7. The key-operable lock mechanism of claim 1, further comprising a return means urging the detent to pivot into the unlocked position upon alignment of the tumbler holes with the detent pins.
 8. The key-operable lock mechanism of claim 7, further comprising a pivot pin, the detent has a depending abutment at the one end thereof, the tumbler support has flanges at the end thereof remote from the keyhole and the keyway passages extending between said flanges, the detent abutment being slotted to receive the tumbler support flanges, the abutment and the flanges having aligned bores receiving the pivot pin whereby the detent is pivotal about the pivot pin on the tumbler support, and said return means being compression springs mounted in the keyway passages between the tumblers and the detent abutment.
 9. The key-operable lock mechanism of claim 1, wherein at least one of the detent pins is longer than the other pins whereby the other pins do not contact the upper surfaces of respective ones of the tumblers in the locked position. 